Lubricating oil scavenging pump



arch 16, 193'].

F. E. STIFTER 2,073,886

LUBRICATING OIL SCAVENGING PUMP Filed April 10, 1935 fzwmrzzsw/zer ATTORNEY Patented Mar. 16, 1937 v PATENT OFFICE LUBRICATING OIL SCAVENGING PUMP Frank E. Stifter, Pittsburgh, Pa., assignor to S. Q. Shannon, Los Angeles, Calif.

Application April 10, 1935, Serial No. 15,692

8 Claims.

This invention relates to pumps more particularly adapted for scavenging excess lubricating oil from the piston and cylinder walls of internal combustion engines, and has for an object to mechanically or focibly purge these parts of excessive oil and return the oil to the reservoir in a short direct path.

A further object is to provide an oil scavenging pump mechanism that may be easily built into new engines or may be applied to engines now in use without extensive alterations, and which in use will be actuated by movement of the engine piston to alternately withdraw surplus oil from the ring grooves and expel it into the oil reservoir.

A still further objectis to provide an oil scavenging pump mechanism that will be formed of a few, simple and inexpensive parts that will be easy to manufacture and in use will not easily get out of order.

With the above and other objects in View, the invention consists in certain novel details of construction and combinations of parts hereinafter fully described and claimed, it being understood that various modifications may be rested too within the scope of the appended claims.

In the accompanying drawing,

Figure 1 is a longitudinal sectional view of the pump mechanism applied to a hollow cylinder of the type common to internal combustion engines.

Figure 2 is a fragmentary bottom plan view of the parts shown in Figure 1.

Figure 3 is a longitudinal sectional view of a modified form of the invention in applied position.

Figure 4 is a fragmentary bottom plan view of the parts shown in Figure 3.

Referring now to the drawing in which like characters of reference designate similar parts in the various views In designates a hollow piston provided in the outer face with circumferential ring grooves l I which receive the usual rings I2, these parts being of the usual and well-known type. In practice oil accumulates in the ring grooves II and surplus oil should be drained 01f to promote high eificiency in operation. To accomplish this purpose I provide pump mechanism which will now be described.

In carrying out the invention a pump cylinder I3 is mounted longitudinally within the hollow piston I0 and preferably is provided at one end with an intake conduit M which is terminally bent so as to readily enter an opening I5 55 formed radially in the wall of the piston l0 and communicating with the bottom of one of the ring or oil grooves i l. A stop collar [6 is formed on the conduit to limit advance thereof into the opening E5. The opposite end of the pump cylinder i3 is provided with a nozzle ll in axial alignment with the cylinder and forming an outlet through which the surplus oil may be returned to the usual reservoir as will presently be explained.

A boss I8 is formed in the wall of the cylinder 53 and is provided with a reduced extension I!) adapted to enter an opening 20 formed in the wall of the piston It]. To rigidly anchor the pump c linder in place a rivet head 2| is formed on the extension l9 as shown.

In order to maintain a tight joint between the conduit and the oil groove l I an arcuate, upwardly arched leaf spring 22 is fixed at one end to the conduit H by means of a suitable connector illustrated as a rivet 23, and the opposite free end bears upon the inner surface of the piston wall diametrically opposite the conduit. -The spring exerts a pressure upon the conduit to hold the stop collar tightly against the inner surface of the piston wall.

Mounted to float within the bore of the pump cylinder 13 is apiston 24 preferably comprising an outer shell 25 having an open threaded end into which a plug 26 is advanced, these parts thus forming a housing for a helical spring 21 which controls a ball check valve 28. An axial passage 29 formed in the plug 26 and a similar axial passage 3!] formed in the shell 25 permits flow of excess oil from the oil groove through the piston, the flow being controlled to one direction only by the ball check valve 28 as will be understood.

The pump piston 24 is confined in the cylinder by opposing helical springs 3i and 32 which bear against opposite ends of the piston. The spring 3| bears against a ball check valve 33 which controls passage of excess oil through the conduit M into the pump cylinder and coacts with the ball check valve 28 in maintaining the flow of oil through the pump cylinder in a single direction. To assemble the piston 24 the springs 3! and 32 and the ball check valve 33, with the pump cylinder l2, the open end I? of the cylinder may be initially left the same in diameter as the cylinder so that the parts may be pushed into place whereupon the open end of the cylinder may be swaged to form the nozzle Ill and con fine the assembly in operative position.

When the engine piston ii! stops for instance at the bottom of its stroke, the pump piston 24 continues to move downwardly and compresses the lower spring 32, at the same time withdrawing oil through the conduit [4 from the oil groove I I, and simultaneously forcing oil out ahead of it through the nozzle [1. The lower helical spring 32 then expands and returns the piston 24 to initial position.

In Figure 3 there is shown a modified form of the device in which the pump cylinder 34 is formed integral with the wall of the hollow piston l0. One end of the cylinder is in communication with the oil groove I I through a passage 35 while the opposite end 36 of the cylinder is open as shown. In the modified form of the invention the piston, opposed controlling springs, as well as ball check valve, are identical in construction with the parts as heretofore described and accordingly have been given the same reference numerals in Figure 3.

After assembling the piston and check valve with the built in pump cylinder 34, a spring washer 3'! may be seated in a recess 38 formed in the cylinder inner wall to confine the parts in operative position.

It is thought that from the above description the construction and operation of my invention will be fully understood without further explanation.

What is claimed is:

1. In an oil scavenging device, the combination of a hollow piston having a ring groove, a pump cylinder disposed longitudinally within the piston and communicating with the ring groove, a spring controlled piston in the cylinder reciprocated by the hollow piston to alternately withdraw surplus oil from the ring groove and expel it from the cylinder, and check valves controlling flow of the oil in one direction through the cylinder.

2. In an oil scavenging device, the combination with a hollow piston having a ring groove, 2. pump cylinder disposed longitudinally within the piston and having a passage communicating with said groove, a pump piston reciprocated by movement of the hollow piston, opposed springs Within the pump cylinder mounting the piston yieldably in the cylinder, a check valve carried by one of said springs and controlling said passage, there being a passage through the pump piston, and a check valve controlling the last named passage, said pump piston alternately withdrawing surplus oil from the ring groove and expelling it from the pump cylinder.

3. In an oil scavenging device, the combination with a hollow piston having a ring groove, of a pump cylinder disposed longitudinally within the piston, a conduit connecting the cylinder with the ring groove, a spring confined under tension between the conduit and the inner-,wall of the hollow cylinder to maintain a tight connection between the conduit and ring groove, a spring controlled piston in the pump cylinder reciprocated by the hollow piston to alternately withdraw surplus oil from the ring groove and expel it from the pump cylinder, and check valves controlling flow of the oil in one direction through the pump cylinder.

4. In an oil scavenging device, the combination with a hollow piston having a ring groove, of a pump cylinder disposed longitudinally within the piston, an intake conduit carried by the cylinder and entering said ring groove, a member on the cylinder wall spaced from the conduit and anchoring the cylinder rigidly to the hollow piston wall, a spring controlled piston in the cylinder reciprocated by the hollow piston to al- .ternately withdraw surplus oil from the ring groove and expel it from the pump cylinder, and check valves controlling flow of the oil in one direction through the pump cylinder.

5. In an oil scavenging device, the combination with a hollow piston having a ring groove, of a pump cylinder disposed longitudinally within the piston, an intake conduit carried by the cylinder and entering said ring groove, an arched leaf spring terminally bearing against the inner wall of the hollow cylinder and exerting tension against the conduit to maintain a tight joint between the conduit and the ring groove, a spring controlled piston in the pump cylinder reciprocated by the hollow piston to alternately withdraw surplus oil from the ring groove and expel it from the pump cylinder, and check valves controlling flow of the oil in one direction through the pump cylinder.

6. In an oil scavenging device, the combination of a hollow piston having a ring groove and having a portion of the wall thickened and provided with a counterbore communicating with the ring groove to form a pump cylinder in the wall of the piston, said cylinder extending longitudinally of the piston, a spring controlled piston in the cylinder reciprocated by the hollow piston to alternately withdraw surplus oil from the ring groove and expel it from the cylinder, and check valves in the cylinder controlling flow of the oil in one direction through the cylinder.

7. In an oil scavenging device, the combination of a hollow piston having a ring groove; a pump cylinder disposed longitudinally within said hollow piston and communicating with said ring groove; an inertia piston in said pump cylinder, reciprecable by axial movement of said hollow piston, to alternately withdraw surplus oil from said ring groove and expel it from said pump cylinder; and check valves within said pump cylinder controlling the flow of oil in one direction through said pump cylinder.

8. A piston comprising a head having a circumferential ring groove; a skirt having opposed thrust faces, one of said thrust faces having a boss provided with a longitudinal bore, one end of said bore communicating with said ring groove through an oil-drain passage; a springpressed check-valve mounted in said bore and controlling the how of oil through said oil-drain passage; an inertia piston reciproeably mounted in said bore below said check-valve, said inertia piston having an axial passage and a springpressed check-valve controlling the flow of oil through said axial passage; and means at the opposite end of said bore to retain said inertia piston in said bore.

FRANK E. STIFTER. 

